PHOTOREGULATORY SIGNAL TRANSDUCTION

光调节信号传导

• 批准号: 2608962
• 负责人: Anthony R. CASHMORE
• 金额: $ 17.72万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-12-01 至 1999-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2608962
• 关键词: Arabidopsis; Baculoviridae; alleles; binding proteins; biological signal transduction; cell membrane; chromophore; electronic spectra; electrophysiology; fusion gene; gene mutation; genetically modified plants; high performance liquid chromatography; molecular genetics; nonvisual photoreceptor; nucleic acid chemical synthesis; oxidation reduction reaction; phosphorylation; photobiology; plant genetics; protein purification; tobacco

The ability to respond to blue light is widespread throughout the biological kingdom. Many of these responses, including some found in bacteria, fungi, insects and plants, are believed to be mediated by flavoproteins. In spite of the fact that blue light responses were first described by Darwin over 100 years ago, no such photoreceptor has hitherto been described. This proposal is based on the recent isolation and characterization of the HY4 gene of Arabidopsis thaiiana. Mutant plants that are defective for this gene show a selective insensitivity to blue light. The sequence of the HY4 gene shows a striking similarity to that of microbial photolyases. These enzymes are a rare class of flavoproteins that repair UV-damaged DNA and are activated by the absorption of either blue or UV light; that is; they function as photoreceptors. This combination of the phenotypic characteristics of hy4 mutants and the sequence similarity to photolyases is compelling evidence that HY4 encodes a flavin-based blue light photoreceptor. This proposal is a combination of biochemical, molecular, and genetic approaches to the further characterization of the HY4 photoreceptor. Collaborative studies involving electrophysiological and biophysical approaches are also included. HY4 will be purified from transgenic tobacco plants, as well as Arabidopsis, and attempts will be made to overexpress it in heterologous expression systems in yeast and baculovirus infected insect cells. The purified protein will be used in studies aimed at determining its biochemical characteristics including the nature of the chromophores. Based on the properties of photolyases, it is believed that HY4 will function as a redox agent. The ability of HY4 to mediate blue light-dependent changes in the redox properties of isolated plasma membranes will be examined and both molecular and genetic approaches will be used to search for additional components in the photoregulatory signal transduction pathway. The ability to perceive and respond to light is universal throughout the biological kingdom and the nature of the signaling mechanisms that are associated with these responses is of wide interest. Equally important, especially in the study of human neutrophils and phagocytosis, is the means by which redox reactions impact on the activity of cellular membranes. The proposed studies, taking full advantage of the merits of both molecular and genetic analysis in Arabidopsis, will provide a significant contribution to our understanding of these important processes.

对蓝光做出反应的能力在整个人体中广泛存在 生物王国。其中许多回复，包括在 细菌、真菌、昆虫和植物被认为是由 黄素蛋白。尽管事实上蓝光反应是最先发生的 达尔文在 100 多年前就描述了这种光感受器，但迄今为止还没有这样的光感受器 被描述。 该提议基于最近的分离和表征 拟南芥的HY4基因。有缺陷的突变植物 该基因对蓝光表现出选择性不敏感。的顺序为 HY4 基因与微生物光裂合酶的基因显示出惊人的相似性。 这些酶是一类罕见的黄素蛋白，可以修复紫外线损伤的 DNA 并通过吸收蓝光或紫外光而被激活；那是; 它们起到光感受器的作用。这种表型组合 hy4突变体的特征以及与光裂合酶的序列相似性 令人信服的证据表明 HY4 编码基于黄素的蓝光 光感受器。 该提议结合了生物化学、分子和遗传 进一步表征 HY4 光感受器的方法。 涉及电生理学和生物物理学的合作研究 方法也包括在内。 HY4将从转基因烟草中纯化 植物，以及拟南芥，并将尝试过度表达 它在酵母和杆状病毒感染的异源表达系统中 昆虫细胞。纯化的蛋白质将用于旨在以下目的的研究： 确定其生化特征，包括其性质 发色团。 根据光裂合酶的性质，认为 HY4 将起到氧化还原剂的作用。 HY4介导蓝色的能力 孤立等离子体氧化还原特性的光依赖性变化 将检查细胞膜，并采用分子和遗传方法 用于搜索光调节信号中的其他成分 转导途径。 感知光和对光做出反应的能力在整个人类中是普遍存在的 生物界和信号机制的本质 与这些反应相关的问题引起了广泛的兴趣。同样重要的是， 特别是在人类中性粒细胞和吞噬作用的研究中， 氧化还原反应影响细胞活性的方式 膜。所提出的研究充分利用了 拟南芥的分子和遗传分析将提供 对我们理解这些重要的内容做出了重大贡献 流程。